Fuzzy modelling for controlled anaesthesia in hospital operating theatres

Balanced anaesthesia introduces the problem of drug interactions. In this paper, the effect concentrations of anaesthetic and analgesic drugs are used to model the pharmacodynamic interactions of the two drugs on the cardiovascular parameters, and on the auditory evoked potentials. An adaptive network-based fuzzy inference system is used to model the different signals. A stimulus model is used to establish the effects of surgical stimulus on the cardiovascular parameters. This model is constructed into a Mamdani type of fuzzy model, using anaesthetist's knowledge described by fuzzy IF–THEN rules. Clinical data are used to construct the patient model.